Glantz's Before Stalingrad, covers the fighting in 1941, from Hitler's invasion on 22 June through Stalin's counter-offensives that December. The book is more accessible and is written and edited for a more general audience than the bulk of Glantz's work. However, Before Stalingrad could serve as one's first book on Operation Barbarossa without losing the reader in minutia.
The book begins with a background chapter on armies, equipment, plans and doctrine. Glantz then breaks down the fighting according to major operations and where appropriate, strategic machinations in the headquarters of both dictators. Each chapter is brought to a close with thorough endnotes. Appendices include Fuehrer Directives plus some Russian planning documents and an excellent order of battle of forces.